TARIFF SCHEDULES OF THE UNITED STATES
SCHEDULE 5. - NONMETALLIC MINERALS AND PRODUCTS Part "> - Ceramic Products
236
Rates of Duty
Subpart A.
Refractory and Heat-Insulating Articles
Subpart A headnot-es: 1. This subpart does not cover ceramic electrical «are (see subpart o of this part). 2. For the purposes of this subpart, "a heatinsulating article", whe^her shaped or not shaped, is one having a bulk density not over 75 pounds per cubic foot and designed to impede or resist the flow of heat at temperatures above I600°F. 3. For the purposes of this subpart, "a refractory article", whether shaped or not shaped, is one having a buIk density over 75 pounds per cubic foot and designed to be used to resist temperatures above 2600°F. A shaped refractory article has special properties of strength and resistance to thermal shock and may also have, depending upon the particular uses for which designed, other special properties such as resistance to abrasion and corrosion. 4. For the purposes of items 531.21 and 531.24, a brick which contains both chrome and magnesite is classifiable according to which of those components is the greater by weight.
531.01 531. Oit 531.11
531.21 531.24 531.27
531.31
531.33 531.35 531.37 531.39
Refractory magnesia, including dead-burned magnesite, fused magnesite, and dead-burned dolomite: Not containing lime or containing by weight not over 4 percent lime Containing by weight over 4 percent lime
0.380 per lb. 125^ ad val.
0.750 per lb. 3 0 ^ ad val.
Refractory and heat-insulating mortars, ramming mixes and castables; super-refractory powders
1 5 % ad val.
30?^ ad val.
25?^ ad val. O.3S0 per lb, 596 ad val. 35^ ad val.
255^ ad val. 0.750 per lb. 105^ ad val. 2 5 ^ ad val.
Free 1 5 ^ ad 1 0 ^ ad 4 5 ^ ad \Ji> ad
Free 4 5 ^ ad 159^ ad 605^ ad 3 0 ^ ad
Refractory and heat-insulating bricks of all sizes and shapes: Chrome bricks Magnesite bricke. Other bricks Shaped refractory and heat-insulating articles not specially provided for, and structures of refractory or heat-insulating articles: Pins, spurs, stilts, and thimbles, all the foregoing used in the manufacture of ceramic articles Carbon or graphite crucibles Earthenware and stoneware crucibles Porcelain refractory articles Other
val. val. val. val.
val. val. val. val.
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